Contact operator



March 8, 1966 N. LESSER CONTACT OPERATOR 2 Sheets-Sheet 1 Filed Oct. 15,1963 f R we m/ U .m f 0 N ATTX March 8, 1966 N. LESSER CONTACT OPERATOR2 Sheets-Sheec 2 Filed Oct. 15, 1965 FIG 7 I N VENTOR. Norfon LesserATTY.

United States Patent 3,239,629 CONTACT OPERATOR Norton Lesser, 648Burton Ave., Highland Park, Ill. Filed Oct. 15, 1963, Ser. No. 317,106 7Claims. (Cl. 200104) This is a continuation in part of applicationSerial No. 98,699, filed March 27, 1961, now abandoned and pertains toan invention which has evolved from the consideration of a number ofproblems presented in the construction and operation of electricalcontacts, These problems include:

(1) Contact erosion and/ or welding.

(2) Power requirements necessary to operate large numbers of contacts.

(3) Securing contact closure and/or opening within required timeintervals.

(4) Enabling the sequential opening and/or closing of contactssimultaneously controlled from a common power source.

(5) Contact gap and spring adjustments.

By the use of a simple insulating card or sheet between respectivecontacts, the severity of the above problems and their economicconsequences can be considerably reduced. In its simplest terms considera pair of break contacts. The springs carrying such contacts arepreformed or stressed so that when assembled the contacts are inengagement under a predetermined degree of spring pressure. Now if aninsulating card be inserted between the contacts they will be heldapart. If an aperture or notch is provided at a predetermined positionin the card and the card moved to bring the aperture into alignment withcontacts, the contacts close under their own spring pressure. They maytherefore be separated by simply moving the card to bring the apertureout of alignment with the contacts. Thus the contacts may be made toserve as either normally open or normally closed contacts depending onthe normal position of the aperture. The gap is determined by thethickness of the insulating card and requires no adjustment. With a cardbetween each set of contacts it becomes a simple matter to move allsimultaneously so that no special adjustment is required to compensatefor the position of the springs in the pile up or other factors. Furtherby locating each aperture in a desired position in its card and/orcontrolling the aperture size both the operate and release time of theassociated contacts may be easily controlled. Further by the locationand size of the aperture the sequence of contact operation may be moreeasily controlled.

In relays or switches where the total movement of the card is limited toa predetermined small increment during which the card may clear thecontacts but fail to clear the springs, a rigid card may preventengagement between contacts. Thus if a rigid card is misaligned withrespect to the plane of the contacts it may fail to disengage from oneof the springs and thereby prevent movement of the spring to bring itscontact into engagement with the contact of the other spring. Thisproblem becomes more severe Where a plurality of contacts are arrangedin a common plane in which the rigid insulator must be in the same planeas each of the contacts. Further a rigid card on engaging the projectingsurface of the contacts is presented with an obstacle which directlyresists its movement and therefore tends to obviate the power gainordinarily derived from the sliding separation of the contacts.

It is therefore desirable to use a plastic or deformable insulator whichyields to some extent to the contact surface and to the spring pressureand thereby avoid rigid engagement with the contact and also permitscontact closure even it slightly misaligned. It has however steel andpreferably soft iron.

"Ice

evidently been heretofore believed that such an insulator wouldcontribute to contact contamination.

To reduce the frictional forces required to move the card especially inthe case of intermittently operated devices such as relays or steppingswitches, where the card is always slid from a rest position, it isdesirable to lubricate the card. Lubrication however, has also evidentlybeen considered as a source of contact contamination in addition tocreating maintainence problems.

The present invention however, utilizes an insulator or card of aplastic or deformable character for operating the contacts and furtherutilizes an insulator having inherent lubricating characteristicsderived from materials having an integrally formed lubricating surfacesuch as provided by polytetnafluorethylene, commonly known as Teflon.Such an insulator is particularly valuable since it is easily shaped orworked and provides a low static coefiicient of friction with the staticcoefficient of friction falling with increasing load and does not resultin contact contamination.

In many types of relays a stainless steel pin is used for pivotablymounting the armature at the end of the heelpiece with the pin beingpivotably held in a yoke adapted to be fastened to the heelpiece. Boththe pin and yoke are fabricated to extremely close tolerance and areexpensive to manufacture and assemble. In addition the armature isusually provided with a nonmagnetic shim in the area where it engagesthe coil core to prevent magnetic sticking; and, in many relays usingcard actuated contacts the armature is returned to its normal positionon coil de-energization by a special return spring.

Some attempts have been made in the past to provide an armature which isfixedly mounted on the end of the heelpiece for avoiding the pin andyoke construction referred to above. Such an armature would usuallyemploy a spring material that is flexed on coil energization and whoseresiliency would avoid the need for a separate return spring in the caseof card actuated contacts. An

armature of spring material however has certain disadvantages forexample, arising from the stresses set up therein if given a sharp bendadjacent the end of the heelpiece in order to maintain a short magneticcircuit. In addition high operating forces are required if the bend orpoint of flexure is comparatively close to the coil core.

It is therefore additionally proposed in the present invention toutilize a relay armature of mild or cold rolled steel and preferably ofsoft iron that is rigidly mounted on the heelpiece and which may begiven a sharp bend at the end of the heelpiece in order to maintain aclosely coupled magnetic circuit without danger of rupturing on repeatedflexing.

A rigidly mounted armature which will flex under normal magnetic fieldshas to be of very thin cross section and therefore will not carry muchflux. In order to render such an armature operable or flexible with amini mum field and to render it sufficiently rigid, it is additionallyproposed to increase the cross section of such an armature in the areaadjacent the coil core and the end of the heelpiece by attaching theretoa plate of mild This increases the flux carried in the critical areasand rigidifies the armature while enabling flexure with a minimum offorce.

Under certain circumstances where the armature is required to operate alarge number of contacts, magnetic sticking may eventually overcome thenormal return forces. To avoid this result the present invention alsocontemplates a spring of non-magnetic material mounted on the armatureand interposed between armature and the core. The non-magnetic spring inthis position serves the dual purpose of aiding the return of thearmature and as a shim to prevent magnetic sticking.

It is also contemplated in the present invention to use an improvedarmature of the type just described for carrying an insulator of thetype described in the previous paragraphs. For this purpose an improvedarrangement for mounting the insulator on the armature is consideredamong the objects of this invention.

The foregoing having described certain advantages and objects of thepresent invention, these together with others will become more clearlyapparent on reading the following specification, claims and drawings;wherein:

FIG. 1 is an illustration of a relay utilizing the principles of theinvention,

FIG. 2 is a view taken along the line 22 in FIG. 1.

FIG. 3 is a perspective view of another manner of controlling theoperation of contacts such as shown in FIG. 1.

FIG. 4 is a view of a bank contact portion of a stepping switch.

FIG. 5 is an illustration of one manner of controlling a make and breakspring contact operation.

FIG. 6 is a side elevational view of a relay partially in cross sectionutilizing the improved armature construction.

FIG. 7 is a top elevational view of the relay shown in FIG. 6; and

FIG. 8 is a sectional view taken along the line 88 in FIG. 6.

In FIG. 1 a relay construction 10 is illustrated. That relay includes acoil 12 adapted to be energized in any well known manner over the leads14 and 16. The coil 12 has a core 18 of appropriate material and iscarried by the heelpiece 20. The bracket 22 is formed on or carried bythe heelpiece 20 and in turn supports the contact or spring pile up 24.

When energized the coil 12 creates a magnetic circuit through theheelpiece 20 and the armature 21 pivotally carried at 19 on one end ofthe heelpiece to attract the I armature 21 to the core 18. The armature21 pivots about 19 to move. its lever arm 23 counterclockwise. Aresidual screw 17 is provided on the armature 21. It limits the armaturemovement so as to provide an air gap between the armature 21 and core 18to thereby prevent the armature from being delayed in returning to itsnormal position on de-energization of the coil 12.

The spring pile up 24 may comprise a plurality of make and/ or breakcontact sets or various combinations there- 26a and 27e are preformed orstressed so that the respective contacts 281 and 29a28e and 29e wouldnormally be in engagement under a desired degree of pressure, in

other words-are formed as break contacts.

An insulating card or sheet 38, however, is inserted between therespective contacts 28a and 29a, 28b and 29b and 28c and 29c to maintainthem normally separated so that they may act as make contacts onenergization of the relays 10. The cards are provided with respectiveapertures 33, 34, 35, 36 and 37 for the respective contact sets. Theapertures 36 and 37 are aligned with respective contacts 28d and 29d and28a and 29:: respectively so that these contacts are normally breakcontacts. The other apertures 33-35 when aligned with their respectivecontacts permit the closure of those contacts under the tension of therespective springs. The cards 38 are supported in any well known mannerby an appropriate bracket 40 to eliminate undesirable flexing. Thedesign of the bracket 40 is of course subject to a number of factors sothat its configuration and structure may vary over wide limits. Thuseach card 38 may be provided with a separate bracket 40 and by suitableguide or stop arrangements each moved in a different manner.

The card 38 may comprise any one of a number of well known types ofmaterials having desired characteristics. Plastics such as, for example,the saturated polyesters one of which is sold under the trade nameMylar: or others such as polytetrafluorethylene sold under the tradename Teflon may be used. Teflon evidently deposits a film on the surfacewith which it is in engagement and this film serves as a lubricant thatprovides a very low coefficient of friction. Such materials haveexcellent dimensional stability, tear or shear resistance, and desirableelectrical and fabrication qualities. The rigidity of the sheet dependsof course upon the quality of the material, its thickness and theunsupported area thereof. The desired normal separation betweenrespective contacts 28a and 29a28c and 290 governs the thickness of thematerial. Normally in telephone circuits utilizing 48 volts, forexample, a gap in the neighborhood of .006" would be provided betweenthe contacts, and in other types the gap may be in the neighborhood oftwice that amount. However, due to the high insulating qualities of thesheet 38 this may be lowered considerably if desired by simply using athinner sheet, or if the gap is to be enlarged a thicker sheet is used.

The bracket 40 is movably supported on the bracket 22 by a pin such as44 engaging a slot 46 in the bracket. The bracket 40 and sheets 38 arebiased in one direction against the lever arm 23 by the spring 42, andthe movement in one direction by the lever arm 21, bracket 40 and sheet38 is limited by the stop 45.

The movement of bracket 40 on energization of the coil is guided by thepin 44 in the slot 46 and is limited by the residual screw 17. When thecoil 12 is de-energized the spring 42 simply retracts the sheets 38 fromtheir operated position.

If it is desired to operate the contacts as break contacts instead ofmake contacts, the position of the aperture is normally aligned with thecontacts as shown, for example, at apertures 36 and 37. The aperture ismoved out of alignment with contacts 36 and 37 when the coil isenergized so that the card 38 opens the contacts. If the contacts are tobe operated as make contacts the card is located between the contactsand on energization of the coil the apertures 33-35, for example, aremoved into alignment with the respective contacts and they close undertheir own tension. If a large number of contact springs are to beoperated in the pile up, this permits all springs to be preformed andassembled in the same manner whether operated as break or make contacts,thus minimizing assembly and spring adjustment and problems as to thegap size for each spring combination. It will be noted that the amountof force necessary to operate the springs need only overcome the bias ofspring 42 and the inertia of bracket 40 and sheet 38, the frictionalforces of the contacts against the sheet 38' and such force as necessaryto initially pry the break contacts apart. The biasing spring inretracting the sheet 40 need only overcome the force involved in thedescribed factors and the mass of the armature and lover arm plus anyresidual magnetism. Since the mass of the elements and the frictionaland prying forces are comparatively nominal, little power is neededeither by the biasing spring in overcoming those forces or by theenergized coil, thus permitting a large number of springs to besimultaneously controlled by the coil. All springs may be of the samegauge and receive the same prestressing or forming.

The time interval at which the contacts are permitted to operate afterthe coil is energized is governed by the location or the size of theaperture and the velocity of the card. By locating the aperture at adesired point from the contacts it must travel x distance as shown foraperture 33 after the coil is energized before permitting contactclosure between 28a and 29a. If the contacts are to open a certain timeinterval after energization the size of the aperture 36, for example, isdimensioned so that it travels y distance before the card 38 separatescont-acts 28d and 29d. Thus a simple expedient is available forgoverning the operating time of the contacts. The release time of themake contacts may be governed by the size of aperture 33. Thus by makingthe aperture large and having the sheet 38 travel some distance afterthe make contacts are closed the contacts 28a and 29a are located wdistance from the aperture edge. Thus on de-energization of the coil 12that distance must be traversed before the contacts open, therebygoverning the release time of the contacts. For break contacts such as28d and 29d the procedure for governing the release time afterde-energization of the coil is simply reversed. Thus by moving the sheet38 some distance z after the break contacts 280. and 29d are open, therelease time of the break contacts is governed by the time periodnecessary to return the aperture 36 into alignment with the contacts.One set of contacts may be made to operate several times for oneoperation of another by simply providing spaced apertures each operatingthe one set of contacts in a desired sequence while another is operatedby a single aperture or hole, for example, or in another sequence.

Inspection of FIG. 2 will also illustrate another facet of theinvention. For example, consider the make contacts 28a and 29a-28c and290. Since the edges 33, 34 and 35 are each spaced a different distancefrom the respective make contacts, those contacts will operate in arespective sequence on energization of coil 12. Thus the contacts 28aand 29a operates before contacts 28b and 29b and 280 and 290. Contacts28c and 290 operate in a time interval after 28a and 29a determined bythe distance between the respective aperture edges. Contacts 281) and29b, of course, operate in another time interval determined by thedistance between aperture 34 and contacts 28b and 2912. With respect tocontacts 28d and 29d and contacts 28e and 29. it will be noted thatcontacts 28:; and 292 will operate or break before contacts 28d and 29ddue to the spacing of the back edges of the apertures 36 and 37.Likewise the spacing of the back edge of aperture 36 with respect to thefront edge of apertures 33 and 35, for example, enables contacts 28a and29a and 280 and 29c to close before contacts 28d-and 29a open. Contacts28e and 29:2, for example, open before contacts 28b and 29b close. Thusa large number of desired sequences of contact operation may be easilyarranged. It will be noted that the use of an aperture in preference tocomplete disengagement of the card enables far superior support to beprovided to edges disengaging the contacts and prevents buckling Onde-energization of the coil 12 the cards 38 travel back to theiroriginal position. The location of the aperture edge with respect to thecontacts will now control the time sequence of contact release. Thuscontacts 28b and 29b open before contacts 28a and 29a. Contacts 28d and29d close before contacts 282 and 29a close or before contacts 28a and29a open, for example. The condition of contact release is thereforealso easily susceptible to control. In addition if the cards 38 are tobe separately guided or moved and/or the apertures given respectiveconfigurations and the cards guided accordingly, the time squence ofcontact operation may be varied in any one of a number of differentmanners.

The previous discussion has contemplated a spring pile up of aconsiderable number of springs in a single aligned array with adifferent sheet 38 between respective contacts. A plurality of sucharrays or contact pile ups 50 as shown in FIG. 3 may be also usedtogether with a simple sheet 52 for operating the respective contacts ineach pile up. Each pile up 50 is mounted in respective spaced apartlocations on a bracket 54 and the single sheet or card is adapted totraverse or engage with one of the contact sets in each pile up. Thisarrangement permits a plurality of contacts to be disposed laterally andoperated simultaneously by a single insulator sheet or card controlledby a relay armature or lever.

The card 52 is moved in any one of a number of well known manners to theright, for example, as shown by the arrow. When this occurs one set ofcontacts in each pile up is operated. Thus the contacts 55 and 56 openas the aperture 57 moves out of alignment therewith. The contacts 60 and61 on the other hand close as the aperture 63 moves into alignmenttherewith. The operative sequence may be controlled as alreadyexplained. In addition another feature is illustrated in FIG. 3. This isan additional arrangement for quench ing any tendency to arc. Thus aconductive coating 65 and 66 may be applied to respective sides of thesheet 52 adjacent the aperture 63, for example, and suitable sparksupression means connected thereto.

The means for moving the sheet need not be limited to a relay, ofcourse, but instead such devices as stepping switches of cams may alsobe used. Thus in FIG. 4 a portion of a multiple level switch 69 is shownhaving a series of sheets 70, 71 and 72 arranged to be given a rotary orsimilar movement. The sheets replace the conductive wipers normally usedand are arranged to engage the respective bank contacts 74, 75 and 76 ofa multiple level bank 77, for example. The contacts are arranged asnormally closed contacts and the respective sheet maintains control oftheir position. In this type of operation usually the first contacts ineach level are operated when the switch is in position 1, and the secondand succeeding contacts of each level are operated when the switch is inposition 2 or respective succeeding positions. The sheets 70, 71 and 72are provided with respective apertures 81 and 82 and the ledge 83. Theposition of these is changed so that they successively engage thecontacts of respective levels in positions 1, 2 and 3, etc. Thus as thecards 70, 71 and 72 rotate to their first position contacts 74 and 75close while contacts 76 open and the ledge or projection 83 openscontacts 76. Due to the position of the edge of aperture 82 with respectto aperture 81, contacts 74 close before contacts 75. Also due to theposition of ledge 83 with respect to aperture 82, the contacts 75 willclose before contacts 76 open. The spacing of the edges may, of course,determine the time of contact operation with respect to card movement.

When the cards 79-72 are moved to the succeeding position, contacts 75open after contacts 74, and contacts 76 close after contacts 75 open.This, of course, is due to the size of the apertures 81 and 82 and theledge 83. Thus a number of control functions similar to those previouslydescribed for a relay may also be facily performed in a rotary switch inaddition to other described advantages. If desired a common stationarywiper appropriately shaped may be used in place of one spring of eachset and the appearance of an aperture between the wiper and spring willpermit closure.

In FIG. 5 a simple arrangement for a set of make and/ or break contactsis shown. A bracket 87 holding a pair of insulating cards 88 and 89having a respective aperture 90 and 91 is arranged to control the makecontacts 92 and break contacts 93. Thus movement of the bracket 87brings the card 89 into alignment with contacts 91 to open thosecontacts. The aperture 90 being brought into alignment with contacts 92permits their closure. Spring 94 may be made to normally assume aneutral position with springs 95 and 96 biased towards spring 94. On theother hand card 88 may be omitted and card '89 can be used to movespring 94 for causing engagement of the contacts 92.

In FIGS. 6, 7 and 8 one practical version of the insulator described inthe previous paragraphs is shown for use with a relay 100 having animproved armature 102 of a character described heretofore. The relay 100comprises a conventional L shaped heelpiece 103 defining a vertical arm104 and a horizontal arm 105. The arm 104 carried a contact bank 106 atits upper end.

The bank 106 includes an insulating structure 107 in which a pluralityof rows of springs 108, 110 and 111 are fixed. The springs 108 of theupper row and 111 of the lower row engage a respective spring 110 of thecenter row to define four sets of respective contacts 113 and 114. Thecontacts 113 are normally closed to enable the completion of anelectrical circuit through terminals 115 while contacts 114 are normallyheld open by one edge of a slot 116 in a Teflon insulator 117 carried atthe upper end of armature 102.

A coil 118 having a core 119 is mounted on the heelpiece below a contactbank 106. When the coil is energized by an electrical circuit completedthrough terminals such as 110, the armature 102 is adapted to beattracted to the end of the core.

The armature 102 comprises a thin sheet 122 of soft iron carrying a softiron plate 124 between the sheet and the core. The sheet preferably isless than .02 and should be approximately .01" for long continuednonstick operations with the four form C contacts illustrated in bank106, while the plate 124 may be between .025" and .070. The sheet 122 isprovided with a sharp bend 126 approximately 90 adjacent its lower end.The bend 126 serves as a point of flexure for the armature whenattracted by the core 119. A horizontal leg 128 extends from the bend.The leg 128 is provided with a slot 130 whereby the armature may beadjustably mounted and fixed on the heelpiece leg 105 by means of ascrew 132 and a clamp washer 134. The bend 126 is approximately .05"from the core while the gap between the plate 124 and the core isapproximately .02" to .025 so that a short closely coupled magnetic pathis provided.

Since the sheet 122 is quite thin it offers little resistance to flexurewhile the heavy plate 124 provides suflicient cross section to carry theflux between the heelpiece and core with the minimum distance possibleprovided between the end of the heelpiece leg 105 and plate 124. Sincethe weight of the plate 124 acts primarily along the longitudinal axisof the sheet 122 and transverse to the bend 126 there is little tendencyfor the sheet 126 to flex about the bend under the influence of theplate, while the plate in turn tends to rigidify the armature in areasother than the bend.

The upper end of the sheet 122 is also provided with a horizontal leg136 that carries the insulator 117 of the type already described or ofthe type described in copending application Serial No. 98,699, nowabandoned. The leading edge of the slot 116 in the insulator 117 islocated between springs 110 and 111 to hold contacts 114 open while theopposite edge of the slot 116 is adapted to be moved between normallyengaged contacts 113 for opening the same on attraction of the armatureto the core. The leg 136 is provided with a depending tang 13 8. Thetang 138 is extended through an alperture in the insulator and bent overafter the edges of the slot 116 are aligned as desired with the contacts113 and 114 to clamp the insulator in position. Actually a number ofsuch tangs or tines may be provided and they may simply pierce theinsulator and be bent over to clamp the insulator. Additional adjustmentmay be provided by flexing the sheet 122 between the upper end of plate124 and the leg 136. An epoxy may cement the tang to encapsulate theinsulator.

It will be noted that backstops are not provided for limiting the returnmovement of the armature 102. This :is another advantage since repeatedblows by the armature against the backstop may throw the armature out ofadjustment. In the relay 100 on the other hand, the angle of the bend126 or any other bend provided in the vertical leg of the armaturetogether with the resiliency of the armature and the pressure of thesprings cooperate to return the armature to the same position on eachoperation.

When the coil 118 is energized the armature 102 is attracted thereto tosimultaneously move the leading edge of slot 116 from between thecontacts 114 to permit them to engage while the opposite edge of theslot separates contact 113. On tie-energization of the coil, the normalresiliency of the soft iron sheet 122 serves to return the armature andinsulator to normal thereby returning the contacts to normal. With thearrangement shown four or five form C contacts are operable onapproximately milliwatts. Under certain circumstances such as when morethan five contacts 113 and 114 are provided, the normal resiliency ofthe sheet 122 may be insufiicient to return the armature after manycycles of operation.

To overcome this situation an elongate spring 144 approximately .005thick and of non-magnetic material is provided. One end of the spring isfastened to the plate 124 at rivet 146 and the other end is locatedbetween the core 119 and the plate 124 so that when the armature isattracted to the core the spring is placed under tension as the armatureapproaches the core while the thickness of the spring serves to spacethe armature from the core to reduce the danger of sticking.

The foregoing is a description of a number of concepts for achievingimproved results in the operation of electrical contacts, and whoseinventive concepts are believed set forth in the accompanying claims.

What I claim is:

1. A switch construction comprising an electromagnetic actuator, onecontact carried by a cantilever spring, another contact carried by acantilever spring for mating with said one contact under the biasingtension of one of the respective springs, and an insulating memberhaving an integral lubricating surface for sliding between said contactsin response to either the energization or deenergization of saidactuator.

2. A spring pile up for use as a switch comprising a plurality ofcantilever springs having a support at one end and arranged in pairswith each pair engaging at a respective point lying on an axistransverse to the longitudinal axis of said springs and on a common linehaving a constant distance from said support and at a substantiallyirrelevant position with respect to each other for extending arespective electrical circuit therethrough, and an electricallyinsulating structure of deformable material material mounted for slidingmovement between said springs of only a predetermined incrementsubstantially perpendicular to each transverse axis for separating thesprings of each pair during said movement.

3. A switch construction in which an electromagnetic actuator isarranged to be successively energized for selecting a different pair ofcontacts for operation on each successive energization of said actuator,the improvement comprising an arrangement for biasing one contact ofeach pair towards engagement with the other contact, and a plasticinsulating member having an integral lubricating surface arranged to bemoved successively a predetermined increment only in response to eachenergization of said actuator to disengage each pair of contactssuccessively.

4. For use in a stepping switch wherein a coil is periodically energizedfor selecting one of a plurality of positions dependent on the order ofthe energization, a spring individual to each position biased formovement in one direction to engage with another spring, and a plasticdeformable sheet insulating member always maintained between the springsat each position and moved only a predetermined increment responsive toeach successive energization of said coil, said member arranged topermit one spring in the position corresponding to the order of theenergization to engage with the other spring while still maintainedbetween said engaged springs.

5. A relay comprising a coil adapted to be energized by an electricalcurrent, a plurality of spring pairs with the springs of each pairadjusted to normally engage at a respective point adjacent common planeto form sets of contacts lying along a common straight line transverseto the longitudinal aXis of each spring pair, a deformable insulatingsheet adapted to be moved in said plane for simultaneously operating allof said spring pairs regardless of the position of said spring pairswith respect to each other, and means for moving said sheet onepredetermined increment only for simultaneously operating all of saidspring pairs responsive to each energization of said coil.

6. A relay comprising a coil adapted to be energized by an electricalcurrent, a plurality of spring pairs with each pair having a supportedend and adjusted to normally engage at a respective point lying along acommon straight line equidistant from said supported end of each springtransverse to the longitudinal axis of each pair, and an insulator ofpolytetrafluorethylene for each pair adapted to be moved a predeterminedincrement only between said spring pairs and substantially parallel tothe longitudinal axis of each pair responsive to the energization ofsaid coil for operating all of said spring pairs irrespective of theposition of said spring pairs with respect to each other.

7. A relay comprising an electrically insulating deformable sheetmaterial having an integral lubricating surface and normally held in oneposition, a coil energized for moving said material from said oneposition to only one other position on each energization of said coil,and a plurality of contacts each carried by a respective cantileverspring biased to bring said contacts into engagement, said materialbeing always disposed between said springs and moved between saidcontacts alternatively when said materizl is either in said one or insaid other position.

References Cited by the Examiner UNITED STATES PATENTS BERNARD A.GILHEANY, Primray Examiner.

ROBERT K. SCHAEFER, Examiner.

R. N. ENVALL, 111., Assistant Examiner.

1. A SWITCH CONSTRUCTION COMPRISING AN ELECTROMAGNETIC ACTUATOR, ONECONTACT CARRIED BY A CANTILEVER SPRING, ANOTHER CONTACT CARRIED BY ACANTILEVER SPRING FOR MATING WITH SAID ONE CONTACT UNDER THE BIASINGTENSION OF ONE OF THE RESPECTIVE SPRINGS, AND AN INSULATING MEMBERHAVING AN INTEGRAL LUBRICATING SURFACE FOR SLIDING BETWEEN SAID CONTACTSIN RESPONSE TO EITHER THE ENERGIZATION OR DEENERGIZATION OF SAIDACTUATOR.